390 CHARACTERISTIC. . 252. 



. 252. BASE OF THE MEDIATE DETERMINATION. 



The mediate determination entirely depends upon 

 the transitions in the series of characters (.221.), 



The mediate determination is effected by a series or con- 

 catenation of varieties, whose terminal member on one side 

 is immediately determinable. This series of varieties is 

 produced by the gradation in the differences of their pro- 

 parties, which likewise represent members of connected se- 

 ries, as it has been amply demonstrated above. But in 

 these series we observe the transitions ; and thus they 

 appear as the base upon which the mediate determination 

 is founded. 



The transitions must always be employed with the neces- 

 sary precautions, as mentioned in .221. But upon this sup- 

 position, the mediate determination is effected with a secu- 

 rity by no means inferior to that of the immediate deter- 

 mination, with which it is in the closest connexion. Mi- 

 neralogy is not the only, part of Natural History which 

 makes use of the mediate determination. It is necessary 

 also in Zoology and Botany, in both of which it is em- 

 ployed; yet it does not occur so frequently in these 

 sciences, because the individuals of the organic kingdoms 

 do not constitute compound masses ; the only case excepted 

 if the individual to be determined has not yet arrived at 

 the state of greatest perfection. In that case the botanist 

 compares a plant, which is not in flower, with another 

 which presents the perfect flower, and with other in- 

 dividuals, representing intermediate stages of efflores- 

 cence, between the perfect immediately determinable plant, 

 and that which he wants to determine, in perfect agree- 

 ment with the rules developed above ; and he knows by 

 experience how far he may extend this comparison, in or- 

 der to obtain results, upon the accuracy of which he may 

 rely. 



